code review 5696071: gc: fix string comparisons for new bool rules

src/cmd/gc/walk.c

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 #include        <u.h>
 #include        <libc.h>
 #include        "go.h"
 
 static  Node*   walkprint(Node*, NodeList**, int);
 static  Node*   mapfn(char*, Type*);
@@ skipping 999 matching lines @@
 
         case OCMPSTR:
                 // If one argument to the comparison is an empty string,
                 // comparing the lengths instead will yield the same result
                 // without the function call.
                 if((isconst(n->left, CTSTR) && n->left->val.u.sval->len == 0) ||
                    (isconst(n->right, CTSTR) && n->right->val.u.sval->len == 0)) {
                         r = nod(n->etype, nod(OLEN, n->left, N), nod(OLEN, n->right, N));
                         typecheck(&r, Erv);
                         walkexpr(&r, init);
+                        r->type = n->type;
                         n = r;
                         goto ret;
                 }
 
                 // s + "badgerbadgerbadger" == "badgerbadgerbadger"
                 if((n->etype == OEQ || n->etype == ONE) &&
                    isconst(n->right, CTSTR) &&
                    n->left->op == OADDSTR && isconst(n->left->right, CTSTR) &&
                    cmpslit(n->right, n->left->right) == 0) {
                         r = nod(n->etype, nod(OLEN, n->left->left, N), nodintconst(0));
                         typecheck(&r, Erv);
                         walkexpr(&r, init);
+                        r->type = n->type;
                         n = r;
                         goto ret;
                 }
 
                 // prepare for rewrite below
                 if(n->etype == OEQ || n->etype == ONE) {
                         n->left = cheapexpr(n->left, init);
                         n->right = cheapexpr(n->right, init);
                 }
 
@@ skipping 1541 matching lines @@
         argtype(fn, n->left->type);
         argtype(fn, n->left->type);
         r = mkcall1(fn, n->type, init, typename(n->left->type), l, r);
         if(n->op == ONE) {
                 r = nod(ONOT, r, N);
                 typecheck(&r, Erv);
         }
         *np = r;
         return;
 }